Semana 12 (Semestre 2)

For this week, the task was to be able to achieve that the simulation magcolloids works at the stablished frequency and angle, and of course at the correct magnetic field. In the paper it says the angle is around 30, and the magnetic field is 7.2 mT, and the only thing that changed was the frequency, starting with 0Hz and 3Hz.
(I did not know how to copy the output)
What we can see at 0Hz is that the particles are attaching to each other and present a brownian motion.

At 6Hz the particles seem to behave like crazy, it can be seen a lot of movement in every direction too fast.

Lammps ratchet.

My first attempt to represent a ratchet with lammps was using figures from the same lammps, and achieve something like this.
It seemed like an amazing idea, until I could not find if it was possible to make, in this case, the cross being moved by the particles, because it is a function that makes the cross spin, but not pretty sure if worked with the forces of the particles.

Approach 2 (Using bonds, and angles, and dihedrals)

So, even though I did not want to be using these things, I did not have other choice, becuase I felt it very difficult to be manpulating too many particles and make them with the correct bonds, and angles and dihedrals.
So to begin with, we want to start the particles in a circle form, which it was achieved.

Pasted image 20241022101818.png

But, to be honest I am very lazy, and tried to automate it with python, to make the bonds and angles, and dihedrals with their respective particles, and I think I achieved it.

Here is an example of data file for the simulation created by the python code.

#LAMMPS Circle Configuration

10 atoms
10 bonds
10 angles
10 dihedrals
1 atom types
1 bond types
1 angle types
1 dihedral types

-20.0 20.0 xlo xhi
-20.0 20.0 ylo yhi
-20.0 20.0 zlo zhi

Masses

1 1.0

Bond Coeffs

1 1.0 1.5

Angle Coeffs

1 1.0 144.0

Dihedral Coeffs

1 10.0 1 180

Atoms

1 1 1 5.0 0.0 0.0
2 1 1 4.05 2.94 0.0
3 1 1 1.55 4.76 0.0
4 1 1 -1.55 4.76 0.0
5 1 1 -4.05 2.94 0.0
6 1 1 -5.0 0.0 0.0
7 1 1 -4.05 -2.94 0.0
8 1 1 -1.55 -4.76 0.0
9 1 1 1.55 -4.76 0.0
10 1 1 4.05 -2.94 0.0

Bonds

1 1 1 2
2 1 2 3
3 1 3 4
4 1 4 5
5 1 5 6
6 1 6 7
7 1 7 8
8 1 8 9
9 1 9 10
10 1 10 1

Angles

1 1 1 2 3
2 1 2 3 4
3 1 3 4 5
4 1 4 5 6
5 1 5 6 7
6 1 6 7 8
7 1 7 8 9
8 1 8 9 10
9 1 9 10 1
10 1 10 1 2

Dihedrals

1 1 1 2 3 4
2 1 2 3 4 5
3 1 3 4 5 6
4 1 4 5 6 7
5 1 5 6 7 8
6 1 6 7 8 9
7 1 7 8 9 10
8 1 8 9 10 1
9 1 9 10 1 2
10 1 10 1 2 3

Unfortunately, the simulation did not work, it explodes, I started with only bonds, it exploded, after that with angles, because for me it was obvious that we need angles to maintain the circle form, and exploded, so maybe with dihedrals we can achieve a more static form, but no, it exploded.